0:00 Intro 1:05 Bias diode & transistor comments 5:55 Matching small signal transistors - comparing several methods 9:41 Installing the diff-pair matched transistors 15:12 Replacing the inverter & CCS transistors 19:41 Replacing the Input buffer & CCS transistors 25:45 replacing some resistors 28:40 Replacing the 17 volt Zener diodes 32:52 Replacing the emitter resistors on the outputs 34:58 Replacing the transistors for the overload protect circuit 38:59 Finishing the module up for testing 40:00 Replacing the power supply rectifier diodes 41:38 Testing the restored board - It doesn't work!!! 47:50 Troubleshooting the problem (problem exists between soldering iron and chair ;)) 56:50 Testing the amp after repair 1:00:27 Rebuilding the other channel 1:15:54 Testing the other channel - Success!
Excellent job, Tony. And yes, we do watch to see you mess up; but that’s only because we are all to familiar with the syndrome. I love your comment, “We found the problem between the soldering iron and the seat.” The work you put into these units are worth more than the units themselves, in my opinion. But you inspire me to try my hand. I get the most out of the troubleshooting. As my old boss used to say (alternately), “What’s changed?” and “Who touched it last?” I was able to follow the Marantz 250 series from start to finish and loved every minute of it.
Hey, you're wearing my watch! Anyway, love your channel, new subber. I've been working on reviving an SX-1080 for the past few weeks in my spare time and found your videos. Very comprehensive and well done! I have 2 SX-1080s, acquired both in 2006. They survived Hurricane Katrina by being in an attic as the house was gutted. I put one into service but the other I stored away as a parts donor. Last month I unearthed it from my tool shed and realized it's a complete unit so I've decided to try to revive it. Powers up but in protect mode. Haven't made a lot of progress yet, I started at the PS board. I find the troubleshooting to be relaxing after work (I work in a calibration lab). Update: it's alive! Love bringing old electronics back from the dead.
Hi Tony. I sure don't watch the videos waiting for you to make a mistake. But when you do, it's sure nice to see you take your time to solve the problem. And, after all, it's part of the fun, isn't it? Otherwise it would only be solder, dessolder and screw tightening! Stay well. As always, thank you!
I also use " Bench Glasses" no good for anything else... but wow what difference when doing close up work. Watching you do the actual work is a big plus in my opinion, following along, observing your technique and so on, is a big help. I always appreciated your ability to explain theory, go through the schematics in detail, and describe your intended repair...but then boom...it was done. I felt cheated...🤣 Anyways... Love your channel, great work, glad your showing the hands on side of the business, much appreciated👍
Solder glasses? Me, me, me; it was me! It really touches my heart that I could share just one thing with you that blesses you, for all that you do and have done to bless us. Well, it just makes my day... Did you add a little extra magnification? Maybe try suspending the camera on a pole, down from the ceiling. Then, the pole would not be in the way of your hands.
They are still prescription glasses. They are multi-focal progressive lenses, but the distance range is set to about 6 feet, intermediate is set at about 2 feet and near vision is very close up. The most common name for them is computer glasses according to my eye doctor. Who knew?
@@xraytonyb That's an interesting set up. I did not want there to be any progression in mine. Mine are set to just one distance = about 12-14" from the object, so that I can still get a soldering iron in, under my nose. They have a bit more magnification than the highest magnification of my progressive set.
Great Job Tony B ! I been working on my Sansui G8000 the left speaker been cutting out due to the tone control off/on bi-pass switch I had to take face off again to re-clean/lub after this it got better but not 100 percent so i cleaned the (Pre/amp/connect( slide button and this fixed my problem I couldn't believe it !!
This is a great series, I have a 250m opened up on my work bench and bought a bunch of capacitors to replace in it. It looks like I have 'ver2' based on what you have shown. My output trans were shorted on one channel and I have those replaced but I getting osc. on that channel.
Hahaha 1:12:00 ish my wife busted out laughing! The second zip tie was clear as day on the video that you went through the cap lead AGAIN...I said "you did it again, Tony" out loud and not 1 second later you said "see, I did it again..."
Tony, today germanium diodes are also available in the TO-35 package (e.g. 1N34A), the same housing as the 1N4148. Maybe that product doesn't suffer of drift and unreliability as the original point contact diode in the DO7 package. B.t.w., drift is why it was used and mounted on that transistor in the first place ?
I like the idea of thermally tying the matched transistor pair. However, I don't think the pair should be encapsulated in heat shrink. The heat shrink is going to retain heat. I think a simple aluminum band, cut from a soda can, wrapped around the heads and secured with a drop of super glue would hold them together and act as a heat sink, to move heat away from the pair. The band could be cut wider than the height of the transistor heads, causing the aluminum tube to extend upward and, thereby, adding mass to the heat sink.
Rotel does this a lot in their designs. Their shrink is really thick , so I’m wondering if holding operation temperature would be better as long as the temp stays stable.
I watched the videos and read through the comments but was wondering if the two flyback diodes were added on the output. I may have overlooked it somewhere.
Hey Tony, I really enjoyed this video. How do you like your desolder rig? I currently use the Hakko gun-looking thing. Yours seems to be much more compact which would be really handy
Bob's your uncle, 1:1515 Tony Did you pick the expression up from our Australian/British restoration hobbyists. Everything is all right Have you constricted any projects using high-power x-ray tubes?
Hey Tony I have a Adcom GFA 535L amp. That has a channel out ..I live in middle Tennessee an have no one here to repair it. I could ship to u an pay you to repair it..an pay for shipping back .. let me know if you would be interested...
0:00 Intro
1:05 Bias diode & transistor comments
5:55 Matching small signal transistors - comparing several methods
9:41 Installing the diff-pair matched transistors
15:12 Replacing the inverter & CCS transistors
19:41 Replacing the Input buffer & CCS transistors
25:45 replacing some resistors
28:40 Replacing the 17 volt Zener diodes
32:52 Replacing the emitter resistors on the outputs
34:58 Replacing the transistors for the overload protect circuit
38:59 Finishing the module up for testing
40:00 Replacing the power supply rectifier diodes
41:38 Testing the restored board - It doesn't work!!!
47:50 Troubleshooting the problem (problem exists between soldering iron and chair ;))
56:50 Testing the amp after repair
1:00:27 Rebuilding the other channel
1:15:54 Testing the other channel - Success!
Excellent job, Tony. And yes, we do watch to see you mess up; but that’s only because we are all to familiar with the syndrome. I love your comment, “We found the problem between the soldering iron and the seat.” The work you put into these units are worth more than the units themselves, in my opinion. But you inspire me to try my hand. I get the most out of the troubleshooting. As my old boss used to say (alternately), “What’s changed?” and “Who touched it last?” I was able to follow the Marantz 250 series from start to finish and loved every minute of it.
Hey, you're wearing my watch!
Anyway, love your channel, new subber. I've been working on reviving an SX-1080 for the past few weeks in my spare time and found your videos. Very comprehensive and well done! I have 2 SX-1080s, acquired both in 2006. They survived Hurricane Katrina by being in an attic as the house was gutted. I put one into service but the other I stored away as a parts donor. Last month I unearthed it from my tool shed and realized it's a complete unit so I've decided to try to revive it. Powers up but in protect mode. Haven't made a lot of progress yet, I started at the PS board. I find the troubleshooting to be relaxing after work (I work in a calibration lab).
Update: it's alive! Love bringing old electronics back from the dead.
Hi Tony. I sure don't watch the videos waiting for you to make a mistake. But when you do, it's sure nice to see you take your time to solve the problem. And, after all, it's part of the fun, isn't it? Otherwise it would only be solder, dessolder and screw tightening! Stay well. As always, thank you!
I also use " Bench Glasses" no good for anything else... but wow what difference when doing close up work.
Watching you do the actual work is a big plus in my opinion, following along, observing your technique and so on, is a big help.
I always appreciated your ability to explain theory, go through the schematics in detail, and describe your intended repair...but then boom...it was done. I felt cheated...🤣
Anyways... Love your channel, great work, glad your showing the hands on side of the business, much appreciated👍
Solder glasses? Me, me, me; it was me! It really touches my heart that I could share just one thing with you that blesses you, for all that you do and have done to bless us. Well, it just makes my day... Did you add a little extra magnification? Maybe try suspending the camera on a pole, down from the ceiling. Then, the pole would not be in the way of your hands.
What type of glasses are they?
Interested too as my reading vision keeps degrading. 🙈 aging is not fun.
They are still prescription glasses. They are multi-focal progressive lenses, but the distance range is set to about 6 feet, intermediate is set at about 2 feet and near vision is very close up. The most common name for them is computer glasses according to my eye doctor. Who knew?
@@xraytonyb That's an interesting set up. I did not want there to be any progression in mine. Mine are set to just one distance = about 12-14" from the object, so that I can still get a soldering iron in, under my nose. They have a bit more magnification than the highest magnification of my progressive set.
"This isn't a space probe...." - thank you Tony, that made me smile on the commute to work, not the easiest thing to achieve :-)
Great Job Tony B ! I been working on my Sansui G8000 the left speaker been cutting out due to the tone control off/on bi-pass switch I had to take face off again to re-clean/lub after this it got better but not 100 percent so i cleaned the (Pre/amp/connect( slide button and this fixed my problem I couldn't believe it !!
This is a great series, I have a 250m opened up on my work bench and bought a bunch of capacitors to replace in it. It looks like I have 'ver2' based on what you have shown. My output trans were shorted on one channel and I have those replaced but I getting osc. on that channel.
Excellent as usual. Thanks for your enthusiasm.....as usual. !!
Hahaha 1:12:00 ish my wife busted out laughing! The second zip tie was clear as day on the video that you went through the cap lead AGAIN...I said "you did it again, Tony" out loud and not 1 second later you said "see, I did it again..."
Tony, today germanium diodes are also available in the TO-35 package (e.g. 1N34A), the same housing as the 1N4148. Maybe that product doesn't suffer of drift and unreliability as the original point contact diode in the DO7 package. B.t.w., drift is why it was used and mounted on that transistor in the first place ?
I like the idea of thermally tying the matched transistor pair. However, I don't think the pair should be encapsulated in heat shrink. The heat shrink is going to retain heat. I think a simple aluminum band, cut from a soda can, wrapped around the heads and secured with a drop of super glue would hold them together and act as a heat sink, to move heat away from the pair. The band could be cut wider than the height of the transistor heads, causing the aluminum tube to extend upward and, thereby, adding mass to the heat sink.
Rotel does this a lot in their designs. Their shrink is really thick , so I’m wondering if holding operation temperature would be better as long as the temp stays stable.
I watched the videos and read through the comments but was wondering if the two flyback diodes were added on the output. I may have overlooked it somewhere.
What you called inverter is mainly known as the VAS (voltage amplification stage) transistor I believe.
Correct. I think I may have explained that in the last video.
Hey Tony, I really enjoyed this video. How do you like your desolder rig? I currently use the Hakko gun-looking thing. Yours seems to be much more compact which would be really handy
I missed a lot. Current source module instead of sense resistor? Going to have to go back and find that.
I noticed you changed the large capacitors but I didn't see it in the video or I missed it. What value caps did you use?
I am unconvinced that Schottky diodes cannot replace germanium diodes. 🙂
So if you take the KSA733 C and give it a twist and redirect the legs, wouldn't you be able to place it?
Did you do a vid on the jig? It's not ringing a bell?
yes there is one - search for transistor matching
@@jeditoto3441 Thanks a lot!!
In my experience more NPN samples tend to higher Hfe than PNP ones.
That's physics for you, controlling electrons works better than controlling holes.
Bob's your uncle, 1:1515 Tony Did you pick the expression up from our Australian/British restoration hobbyists. Everything is all right
Have you constricted any projects using high-power x-ray tubes?
which solder iron and mobile phone model u use plz
Purple Legoman head
Hey Tony I have a Adcom GFA 535L amp. That has a channel out ..I live in middle Tennessee an have no one here to repair it. I could ship to u an pay you to repair it..an pay for shipping back .. let me know if you would be interested...
One suggestion, if allowed. Not What??, but Yes Dear, using a cheery voice. Other than that, great learning session! Enjoyed watching! Thanks!